Class-specific immunoaffinity monolith for efficient on-line clean-up of pyrethroids followed by high-performance liquid chromatography analysis

A class-specific monolithic immunoaffinity column was developed for on-line clean-up of pyrethroid insecticides in complex samples. Deltamethrin was oxidized with ozone to generate the hapten of (RS)-α-cyano-3-phenoxybenzyl (RS)-cis,trans-2,2-dimethyl-3-formyl-cyclopropane carboxylate. Class-specific antibodies against pyrethroids were produced using the conjugate of above hapten with bovine serum albumin as the immunogen. Poly(ethylene dimethacrylate-glycidyl methacrylate) monolith was synthesized in a 50 mm × 4.6 mm i.d. stainless steel cartridge with two auxiliary pipette tips. The polymerization method was proved to be economic and reproducible. Antibodies against pyrethroids were covalently immobilized onto the monolithic support via Schiff base reaction. With a column-switching valve system, the immunoaffinity monolith (IAM) could be readily adapted to the reversed-phase high-performance liquid chromatography (HPLC) system. Under the optimum loading, washing and eluting conditions, the IAM specifically retained deltamethrin, flumethrin, flucythrinate and cis/trans permethrin, which were further baseline separated by C18 column using acetonitrile-water (83:17, V/V) as the mobile phase at a flow rate of 1.0 mL/min. The established system provides a highly efficient approach for high-throughput on-line clean-up of pyrethroid in various samples.